ON PTYCHODEEA FLAVA. 173 



ticula or cross-bars of the pharynx. He says (loc. cit., p. 726), 

 "Bei den Enteropneusten sind die Synaptikel stabformige 

 Sprossen, welche zwischen einer Zungen- und einer Septal- 

 zinke ausgespannt sind. . . . Anders beim Amphioxus. Dort 

 sind .... die Synaptikel .... zwischen zwei Septalzinken 

 ausgespannt und der dazwischen liegenden Zungezinke nur 

 angelagert." 



A glance at fig. 3 accompanying this paper will, I think, 

 show conclusively that the above quotation represents merely a 

 subjective mode of expression. In P. flava the synapticula 

 on one side of a tongue-bar are approximately often quite 

 opposite to those on the other side. As the skeleton of the 

 wide tongue-bar is separated into two halves, the synapticula 

 must necessarily likewise be separated. 



By insisting on detailed differences, and more or less neglect- 

 ing the broader distinctions to which they are subordinate, 

 and which would in great measure account for the former, 

 one can really arrive at any conclusion to which the individual 

 mind is inclined. 



To see the synapticula in P. flava the pharyngeal wall 

 must be viewed from the inside, since, as pointed out by Spengel, 

 these structures are placed towards the inner side of the gill- 

 bars, and not on their outer face as in Amphioxus. I have found 

 it a good method to kill in dilute formol, and having removed 

 and opened out the pharynx to mount it in the same liquid. 

 It is well to cut away portions of the genital pleura before 

 preservation in formol, as they are otherwise liable to become 

 glued together in the dorsal middle line. 



The number of synapticula in a vertical or dorso-ventral 

 series in P. flava is from ten to thirteen. In this species, as 

 in the majority of Enteropneusta, the gill-bars are not straight 

 as they are in Amphioxus approximately, but are markedly 

 bowed, the convexity facing outwards. 



Gonads of P. flava. 

 Another remarkable feature of the species under considera- 

 tion, which it presents in common with P. erythroea, P. 



